Metal Ion Dependence of Pyrophosphate-Dependent Phosphofructokinase

다국어 초록 (Multilingual Abstract)

Cr(H₂O)₄ PPi was synthesized to test two metal dependent phosphorylation theory of fructose 6-phosphate by pyrophosphate-dependent phosphofructokinase. Cr(H₂O)₄ PPi acted as a competitive inhibitor in the absence of second metal ion with two dissociation constants indicating the possibility of the presence of activation site by pyrophosphate. To test whether or not Cr(H₂O)₄ PPi acts as a substrate, ［³²P］Cr(H₂O)₄PPi was synthesized and incubated in the presence of second metal ion. The results indicate that Cr(H₂O)₄PPi acts as a substrate in the presence of second metal ion with a thousandth of regular activity. After binding of Cr(H₂O)₄PPi , saturation of MgPPi did not recover the activity completely indicating tight binding of Cr(H₂O)₄PPi . In other words, only binding of pyrophosphate before Cr(H₂O)₄PPi protects the inhibition completely.